.NET 4.5桌面应用中匹配urlencoder.org的C#编码方法

First, let's break down the key differences between .NET's default encoding methods and the result you got from urlencoder.org:

• Space handling: urlencoder.org uses %20 for spaces, while most .NET methods use + (following the application/x-www-form-urlencoded standard, intended for form data rather than raw URL paths).
• Character encoding: The á in your string is encoded as %C3%A1 (UTF-8) by urlencoder.org, but your .NET tests returned %E1 (ISO-8859-1/Latin-1) — this suggests a mismatch in the encoding being used for the character.
• Case preservation: urlencoder.org keeps your original casing (e.g., De stays De), while your .NET results showed lowercase de — this is likely a test input inconsistency, as .NET's encoding methods don't modify string casing.

To replicate urlencoder.org's behavior in .NET 4.5, you'll need a custom method that strictly uses UTF-8 encoding and replaces spaces with %20 instead of +. Here's a reliable implementation:

using System.Text;

public static class CustomUrlEncoder
{
    public static string EncodeLikeUrlEncoderOrg(string input)
    {
        if (string.IsNullOrWhiteSpace(input))
            return input;

        byte[] utf8Bytes = Encoding.UTF8.GetBytes(input);
        StringBuilder encodedBuilder = new StringBuilder();

        foreach (byte b in utf8Bytes)
        {
            // Keep unreserved characters as-is (per RFC 3986)
            if ((b >= 'A' && b <= 'Z') || 
                (b >= 'a' && b <= 'z') || 
                (b >= '0' && b <= '9') || 
                b == '-' || b == '_' || b == '.' || b == '~')
            {
                encodedBuilder.Append((char)b);
            }
            else
            {
                // Encode all other bytes as %XX in uppercase
                encodedBuilder.Append($"%{b:X2}");
            }
        }

        return encodedBuilder.ToString();
    }
}

How to use it: #

string originalString = "Radio Signal Gabriel Moraes,fernando De Sá";
string encodedString = CustomUrlEncoder.EncodeLikeUrlEncoderOrg(originalString);
// Result: Radio%20Signal%20Gabriel%20Moraes%2Cfernando%20De%20S%C3%A1

Why your existing .NET methods didn't match: #

1. HttpUtility.UrlEncode: Uses + for spaces and defaults to the system's default encoding (which might be ISO-8859-1 on your machine) unless you explicitly specify UTF-8. Even with UTF-8 specified, it still uses + instead of %20.
2. Uri.EscapeDataString: In .NET 4.5, this should use UTF-8 and encode spaces as %20, but if your input string's á was stored as an ISO-8859-1 byte instead of a Unicode U+00E1 character, it would still encode to %E1. Double-check that your original string uses proper Unicode characters.
3. Uri.EscapeUriString: This method is designed for escaping entire URIs, not individual segments, so it may skip encoding certain characters that urlencoder.org handles.

内容的提问来源于stack exchange，提问作者Keith Boynton